Mice and guinea pigs will be exposed to an aerosol suspension of microconidia of Blastomyces dermatitidis to simulate natural exposure conditions. Lung lavages will be performed at appropriate times to harvest resident cell populations. The alveolar cells may be the primary host defense to offending inhalants and will be monitored for cell mediated responses: 1. Lymphocyte transformation, using ASWS antigen on these alveolar cells, should provide information on the level of response versus time after exposure; 2. Phagocytic index and intracellular kill, using adherent lavaged cells, will indicate specific and non-specific activation of the alveolar cells. Additional work on production of antibody to the ASWS antigen and determining if a specific component can be obtained by purification on affinity chromatography will be addressed.